Bleed air temperature regulation system: modeling, control, and simulation

This paper addresses temperature control of an engine bleed air system, as used on typical aircraft, with a control strategy aimed at reducing ram air usage while maintaining fast response. The analytical equations describing the system are derived, and a state space model of a cross-flow heat exchanger is developed. Three control strategies are analyzed and compared. Using control valves in both ram-air and bypass channels, along with the addition of controlling both the load temperature and the bypass valve opening, is proposed and proves to be the best control strategy in terms of reducing ram air usage and maintaining efficient temperature control in the presence of various disturbances and system operation conditions. Conclusions are drawn based on simulations